CBR just failed it’s MOT due to the front brake lever not activating the rear brake light.
Strange as before I took it to the MOT it was working fine.
After riding it home and parking up it suddenly starts working again.
An hour later had another go and it’s stopped working.
Dirty switch requiring a clean maybe?
Oh well - gonna go through the usual problem solving routine starting off with giving the switch a squirt of contact cleaner.
Had the exact same issue on my Car, worked going to the MOT station (I know as I checked all lights) didn’t work at the MOT station and failed! Worked when I got home!!!
Turns out it was water ingress in the Tail light unit. Could be something similar for you (worth checking)
Possibly the microswitch under the lever, often the connectors to the microswitch. They get a fair bit of weather and they are usually bog-standard mini spade connectors.
I’m with Scorch. WD40 is your friend
Thanks for the wise words guys - yeah - think I’ll take a look at the switch first and clean up the contacts etc.
+1 on the WD40 to chase the gremlins out 
Thanks Art - gonna take a look at the switch today 
Amazing - I found a video online explaining how to fix this problem - and it wasn’t just a random motorcycle - it was a CBR! - apparently it’s common on CBR’s - and come to think of it I had the exact same problem with a Hornet a few years back (same switchgear as the CBR) - I remember taking the switch apart and bodging a fix that time - this time with the aid of the video I have been able to do a far more elegant job.
I took the switch apart and inspected the internal contacts (the two bits of metal - one spring loaded - which complete the circuit and switch the light on when the lever is pulled in). The contacts were tarnished, so I followed the instructions in the video below and now the brake light switch is working properly again.
lovely jubbly
10 out of 10 for Mr Scorch for the correct diagnosis
Yep - Scorch on the money as usual
